The adufe (also known as
pandeiro quadrado, pandero cuadrado)
is a double-headed square, triangle, or rectangle-shaped
frame drum mainly played in Portugal and Spain (similar
square-shaped frame drums were also found in Egypt
dating back as far as 1400 BC). It can have pellet
bells attached to the inside frame. These frame drums
are usually hand beaten. There is also a particular
Spanish version that is played while sitting while
the right hand uses a stick to strike the frame and
skin with the left hand playing the skin on the opposite
side.

The top photo is an adufe
with pellet bells inside from Spain. Pictured in the
middle and bottom are various adufe made
by Paulo
Meirinhos from Portugal. He makes these instruments
in many shapes including square, hexagon, octagon,
triangle, diamond, and circle. He has also modernized
the tuning design for his drums by including a pneumatic
tuning system.